1. Field of the Invention
The present invention relates to a card, e.g., a PC card, that is detachably inserted to an information processing terminal, including a personal computer and a portable information terminal, when used.
2. Description of the Related Art
Information processing terminals, including a personal computer and a portable information terminal, are capable of having a detachable PC card inserted/attached to it. Examples of such PC cards are a memory card utilized as a storage medium, a modem card for wire communication, an ISDN card, a LAN card, a wireless LAN card for wireless communication, and a PHS card. By using those PC cards, a personal computer or a portable information terminal is flexibly adaptable for various situations and environment under which it is employed. For example, communication can be performed using a LAN card when the environment allows for the use of wired LAN, and using a wireless LAN card when the environment allows for the use of wireless LAN.
When using a PC card, a card connector is inserted to a PC card slot of a PC card interface provided in an information processing terminal in conformity with the PC Card Standards of PCMCIA (Personal Computer Memory Card International Association). When a PC card is not used, the card connector can be withdrawn from the PC card slot.
Recently, with the reduction in size of information processing terminals, cards having smaller sizes have been put into the market. In particular, a Compact Flash (abbreviated to xe2x80x9cCFxe2x80x9d hereinafter) card proposed by CFA (Compact Flash Association) is already utilized in a small-sized information processing terminal such as a digital camera and a portable information terminal. With the advent of CF cards, adaptable for the above-mentioned various functions, it has become possible to provide cards having smaller sizes and more convenient portability.
A PC card has a 68-pin connector and employs a parallel data bus up to 32 bits as a host interface. On the other hand, a CF card has a 50-pin two-piece connector and employs a parallel data bus up to 16 bits, as a host interface.
Further, with recent widespread usage of digital equipment, the ability to form wireless networks everywhere including offices, homes and so on, has received attention. Particularly, the short-distance wireless communication standard called xe2x80x9cBluetoothxe2x80x9d is known as a technology that was developed for connection between a notebook personal computer and a portable telephone. Application of the Bluetooth technology has spread over all kinds of electronic equipment without being restricted by frames represented by peripheral equipment.
Bluetooth technology is also adapted for speech communication and is able to use a line-exchange type SCO (Synchronous Connection Oriented) link that establishes a connection, ensuring real-time correspondence. With an SCO link, a communication time (time slot for communication) is allocated beforehand, and data is transmitted and received at constant intervals. In general data communication, a packet-exchange type ACL (Asynchronous Connection-Less) link is employed. With the ACL link, a communication time is not particularly allocated, and data is transmitted and received only as the occasion requires. Using an ACL link for speech communication causes deterioration in real-time correspondence and sound quality due to a packet delay.
FIG. 11 shows one example of a configuration of a general Bluetooth communication environment. A Bluetooth host 1100 is capable of establishing connections to an IP network 1103 and a line exchange network 1104 which are installed as parts of a communication infrastructure. Also, in FIG. 11, a Bluetooth data terminal 1101 and a Bluetooth cordless telephone 1102 are provided as Bluetooth terminals to form an environment in which a 1:2 piconet can be formed. The Bluetooth data terminal 1101 is able to establish connection for data communication to the IP network 1103 via the Bluetooth host 1100, by using the ACL link. Simultaneously, the Bluetooth cordless telephone 1102 is able to establish a connection for real-time speech communication to the line exchange network 1104 via the Bluetooth host 1100 by using the SCO link. The Bluetooth host 1100 also is capable of processing both the ACL link and the SCO link at the same time.
FIG. 12 shows a configuration of a Bluetooth communicating section built in the Bluetooth host 1100. Numeral 1204 denotes a base band unit having the function of a link controller only, or the functions of both a link controller and a link manager for Bluetooth. The base band unit 1204 has a data communication signal line 1206 corresponding to the ACL link and a speech communication signal line 1207 corresponding to the SCO link. A host CPU 1200 is connected to the base band unit 1204 via a data communication interface 1202 and supervises overall control of the Bluetooth host 1100. The data communication interface 1202 has, for example, the function of making it adaptable to the format enabling the data communication signal line 1206 to be directly connected to a data bus of the host CPU 1200, or the function of making it adaptable to the format of a serial data communication line so that matching with a peripheral device interface of the host CPU 1200 can be established. The speech communication interface 1203 has the function of making it adaptable to a digital signal, e.g., a PCM (Pulse Code Modulation) signal, and an analog signal so that the speech communication signal line 1207 of the base band unit 1204 is connected to a speech processing unit 1201. The speech processing unit 1201 has the function of establishing an electrical interface adapted for the line exchange network 1104 shown in FIG. 11. Although the data communication interface 1202 and the speech communication interface 1203 are built in the base band unit 1204, both interfaces will be described below as being separated from each other for convenience of explanation. Data communication through the ACL link is performed via an RF unit 1205 for transmitting and receiving data with wireless communication, the base band unit 1204, the data communication interface 1202 and the host CPU 1200. Speech communication, maintaining real-time correspondence through the SCO link, is performed via a route separated from the data communication interface 1202, downstream of the base band unit 1204, and then passing the speech communication interface 1203 and the speech processing unit 1201.
Hitherto, PC and CF cards adapted for a Bluetooth communication function have been constructed such that all kinds of communications between a base band unit and a host CPU for the Bluetooth communication pass through a bus interface. FIG. 13 shows a configuration of a conventional Bluetooth-adapted PC card. An RF unit 1305 and a base band unit 1304 are the same as those shown in FIG. 12. A data communication signal 1303 from the base band unit 1304 is converted by a PC bus controller 1302 into a bus signal 1301 having the bus format adapted for a PC bus. The converted bus signal 1301 is introduced to a PC card connector 1300. However, a speech communication route from the base band unit 1304 is not provided, or is held in a non-use state.
FIG. 14 shows a PC card interface section of a conventional host. A PC card connector 1400 is connected in the bus signal format to a host CPU 1402 via a PC bus controller 1401. Thus, in a conventional wireless communication device, the PC card connector 1300 of the PC card is connected to the PC card connector 1400 of the host, and the base band unit 1304 is coupled to the host CPU 1402 through the PC card bus interface.
The CF card also has a similar configuration to that of the PC card.
Because, as described above, a Bluetooth communicating section incorporated in a PC or CF card is constructed such that a data signal line from a base band unit is adapted only for an ACL link coupled in the bus format for packet communication, the following problems are experienced.
Even when a PC or CF card slot is provided and a PC or CF card can be used, good speech communication maintaining real-time correspondence cannot be achieved and hence the card is not adaptable for various situations and environments in use.
Also, to be adapted for the SCO link, another Bluetooth module for the SCO link must be incorporated in a host. The necessity of additionally incorporating a dedicated module increases the cost and is uneconomical.
On the other hand, if a PC or CF card adapted only for the SCO link is provided, a host having a conventional standard bus interface adapted for the ACL link cannot handle such a card. Therefore, a host provided with a new PC or CF card slot specifically adapted for the SCO link must be provided, and this necessity also increases the cost and is uneconomical. Further, flexibility of a card slot, i.e., an intrinsic feature of a card slot being flexibly adapted for various environments in use, is lost from a host. On the user side, there occurs a problem in that combinations between a card to be used and a host are different depending on applications, and this increase in complexity is troublesome and inconvenient to the user.
Accordingly, it is an object of the present invention to provide a card having a communication function which is adaptable for use in various environments.
Another object of the present invention is to provide a card having a communication function which can selectively set an interface and handle a plurality of signal forms by a single card.
Still another object of the present invention is to provide a card having a communication function which is economical and convenient to use.
According to one aspect, the present invention which achieves these objectives relates to a card having a communication function, comprising:
first interface means for performing communication in a first card bus signal format between a host and a base band unit which provide communication links for data and speech with wireless communication;
second interface means for communicating data and speech at the same time in a second signal format between said host and said base band unit;
coupling/separating means for coupling and separating said host and a wireless communication module through the insertion/withdrawal of a card, wherein said coupling/separating means is shared, in which said first interface means is connected to said host and said second interface means is connected to said host; and
switching means for selectively switching over between a mode for executing communication with said host using said first interface means and a mode for executing communication with said host using said second interface means, in which said card is connected to said host through said coupling/separating means.
According to another aspect, the present invention which achieves these objectives relates to an adapter having a communication function, comprising:
first interface means for performing communication in a first signal format between a communicating unit and another unit which provide communication links for data and speech;
second interface means for performing communication in a second signal format between said communicating unit and said another unit;
coupling/separating means for coupling and separating said another unit and said communicating unit, wherein said coupling/separating means is shared, in which said first interface means is connected to said another unit and said second interface means is connected to said another unit; and
switching means for selectively switching over between a mode for executing communication with said another unit using said first interface means and a mode for executing communication with said another unit using said second interface means, in which said adapter is connected to said another unit through said coupling/separating means.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.